Philadelphia Police Officers remain on high alert and have been ordered to now ride in pairs, since the recent ambush of officer Hartnett which occurred on January 7. 2016 and especially after receiving information from a woman stating, there are more men connected to the suspect, more radical than he, and there could possibly be more ambush attempts on other police officers.
The Philadelphia Police Department released a statement on there Facebook page:

The Philadelphia Police department and the the F.B.I. are conducting full investigation.